Nickel-catalysed highly regioselective synthesis of ß-acyl naphthalenes under reductive conditions.

Over the past decade, significant progress has been made in the direct C-H acylation of naphthalenes, occurring at the α or ß-positions to yield valuable ketones through Friedel-Crafts acylation or transition-metal-catalysed carbonylative coupling reactions. Nevertheless, highly regioselective acylation of naphthalenes remains a formidable challenge. Herein, we developed a nickel-catalysed reductive ring-opening reaction of 7-oxabenzonorbornadienes with acyl chlorides as the electrophilic coupling partner, providing a new method for the exclusive preparation of ß-acyl naphthalenes.

Nickel-catalysed chelation-assisted reductive defluorinative sulfenylation of trifluoropropionic acid derivatives.

Herein we reported a directing-group assisted strategy for nickel-catalysed reductive defluorinative sulfenylation of trifluoropropionic acid derivatives with disulfides in the presence of Zn, involving triple C-F bond cleavage. This process yielded a diverse array of carbonyl-sulfide di-substituted alkenes in moderate to good yields with good functional group tolerance. Specifically, the reactions exhibited high E-selectivity with E/Z ratio up to >99 : 1.

Ligand Relay for Nickel-Catalyzed Decarbonylative Alkylation of Aroyl Chlorides.

Transition metal-catalyzed direct decarboxylative transformations of aromatic carboxylic acids usually require high temperatures, which limit the substrate's scope, especially for late-stage applications. The development of the selective decarbonylative of carboxylic acid derivatives, especially the most fundamental aroyl chlorides, with stable and cheap electrophiles under mild conditions is highly desirable and meaningful, but remains challenging. Herein, a strategy of nickel-catalyzed decarbonylative alkylation of aroyl chlorides via phosphine/nitrogen ligand relay is reported. The simple phosphine ligand is found essential for the decarbonylation step, while the nitrogen ligand promotes the cross-electrophile coupling. Such a ligand relay system can effectively and orderly carry out the catalytic process at room temperature, utilizing easily available aroyl chlorides as an aryl electrophile for reductive alkylation. This discovery provides a new strategy for direct decarbonylative coupling, features operationally simple, mild conditions, and excellent functional group tolerance. The mild approach is applied to the late-stage methylation of various pharmaceuticals. Extensive experiments are carried out to provide insights into the reaction pathway and support the ligand relay process.

Iron-catalysed reductive coupling for the synthesis of polyfluorinated compounds.

Herein we reported the use of Earth-abundant iron as the catalytic metal in the presence of Mn to induce difluorobromoacetates to form carbon radicals, which reacted with trifluoromethyl olefins followed by ß-F elimination to generate the corresponding gem-difluoroolefins. The cross-electrophile coupling displayed excellent functional group tolerance and broad substrate scope under mild reductive conditions, affording a large number of polyfluorinated compounds, which could be further transformed to other valuable molecules.

Synergistic Gold and Iron Dual Catalysis: Preferred Radical Addition toward Vinyl-Gold Intermediate over Alkene.

A dual catalytic approach enlisting gold and iron synergy is described. This method offers readily access to substituted heterocycle aldehydes via oxygen radical addition to vinyl-gold intermediates under Fe catalyst assistance. This system shows good functional group compatibility for the generation of substituted oxazole, indole, and benzofuran aldehydes. Mechanistic evidence greatly supports selective radical addition to an activated vinyl-Au double bond over alkene. This unique discovery offers a new avenue with great potential to further extend the synthetic power and versatility of gold catalysis.